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MED1473

landing distances

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RTO is the strongest braking on the plane. That's when you can get fuse plugs melting

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If you haven't tried the B737NG dispatch sheet for excel can find it at avsim file library: http://library.avsim.net/esearch.php?CatID=fsxutil&DLID=180540

 

It calculates the required landing distance based on speed, brake settings, weather, and runway conditions. It easy to change the factors and see the results.

 

One thing to remember though. The Required Landing Distance is longer that the expected landing role. It includes safety margins. If i remember correctly it adds 300ft to tresshold plus a percentage of the calculated roll distance depending on conditions.

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This discussion seems to come up every year in recurrent training. This is my understanding:

 

Manual gives you up to 3000psi based on how hard you push with your feet (it could be less). Max Auto gives you up to 3000psi based on 8.3kts/sec above 80kts and then 7.0kts/sec deceleration.

Yup, according to my book The Boeing 737 Technical Guide your understanding is correct, thanks for correct me. Another thought is that the maximum normal pressure range of the hydraulic system is 3000 - 3500psi. Where MAX is capped at 3000psi, RTO is uncontrolled and I assume will use all the pressure available to it, which could mean up to 3500 psi on the day with maximum deceleration all the way to standstill. This is the same for MAX MANUAL.

 

 

 

I don't think I want to experience 3000psi with good braking. I'll be happy with 8.3kts/sec or less. If you need more than that, something is seriously wrong.

Have you noticed how the MAX setting is on a latch, you have to pull the control knob out to select it. Perhaps Boeing's way of saying "Seriously - are you sure about this?" :blink:

 

keeping track and flying the nose down enough to commence manual braking of his own.

Nothing dramatic, but I have noticed with Autobrake 3 and specifically landing at a high altitude airfields with a landing ground speed of about 160kts, the deceleration rate is such that the nose has a tendency to drop much very quickly unless slowed with judicious back pressure on the column.

 

 

 

The Required Landing Distance is longer that the expected landing role. It includes safety margins. If i remember correctly it adds 300ft to tresshold plus a percentage of the calculated roll distance depending on conditions.

Landing performance in the Flight Planning Performance Manual (not included with NGX) and the Performance Dispatch (included in FCOM1) is certified and factored data and doesn't assume the use of reverse. The Performance Inflight (FCOM1 and QRH) is unfactored and is what the crews use to calculate landing performance for the actual conditions and assumes the use of reverse thrust (different operators may have not include reverse thrust in their tables). Using this data you can expect the aircraft to stop in the quoted distances. So, if you float the landing you will most likely not meet the numbers.

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